<< A while ago someone posted a demonstration of the Lucas-Lehmer test for, I think, 2^7-1. >> LL test: S[0] = 4 S[k+1] = S[k] ^2 - 2 mod 2^P - 1 2^P - 1 is prime if and only if S[P-2] = 0. Demonstration for 2^7 - 1 = 127: S[0] = 4 S[1] = 4^2 - 2 mod 127 = 14 S[2] = 14^2 - 2 mod 127 = 194 mod 127 = 67 S[3] = 67^2 - 2 mod 127 = 4487 mod 127 = 42 S[4] = 42^2 - 2 mod 127 = 1762 mod 127 = 111 S[5] = 111^2 - 2 mod 127 = 12319 mod 127 = 0 S[7-2] = S[5] = 0, hence 2^7 - 1 is prime. QED YEA STL _________________________________________________________________ Unsubscribe & list info -- http://www.scruz.net/~luke/signup.htm Mersenne Prime FAQ -- http://www.tasam.com/~lrwiman/FAQ-mers
